Ophthalmic apparatus

Abstract

An ophthalmic apparatus includes: a light projecting optical system for projecting measurement light on a cornea of an examinee's eye; a first imaging optical system for imaging a cornea reflection image obtained by reflection of the measurement light at the cornea; a computing unit for obtaining a direction of a corneal astigmatic axis based on the cornea reflection image; an illuminating optical system for projecting illumination light toward a fundus of the examinee's eye; a second imaging optical system for imaging a retro-illumination image in a pupil of the examinee's eye obtained by reflection of the illumination light at the fundus; an image processing unit for combining a first target representing the direction of the astigmatic axis with the retro-illumination image; and an output unit for outputting the retro-illumination image with which the first target has been combined.

What is claimed is: 
     
       1. An ophthalmic apparatus, comprising:
 a light projecting optical system for projecting measurement light on a cornea of an examinee's eye; 
 a first imaging optical system for imaging a cornea reflection image from reflection of the measurement light at the cornea; 
 a computing unit for obtaining a direction of a corneal astigmatic axis based on the cornea reflection image; 
 an illuminating optical system for projecting illumination light towards a fundus of the examinee's eye; 
 a second imaging optical system for imaging a retro-illumination image in a pupil of the examinee's eye from reflection of the illumination light at the fundus; and 
 an image processing unit for superimposing a first target representing the direction of the corneal astigmatic axis obtained by the computing unit based on the cornea reflection mage on the retro-illumination image. 
 
     
     
       2. The ophthalmic apparatus according to  claim 1 , further comprising a TORIC-Intraocular lens inserted in the examinee's eye, wherein
 the computing unit is adapted to obtain a direction of an astigmatic axis of the TORIC-Intraocular lens based on the retro-illumination image, and 
 the image processing unit is adapted to further superimpose a second target representing the direction of the astigmatic axis of the TORIC-Intraocular lens on the retro-illumination image together with the first target. 
 
     
     
       3. The ophthalmic apparatus according to  claim 2 , wherein
 the TORIC-Intraocular lens includes an astigmatic axis mark formed thereon, and 
 the computing unit is adapted to measure the direction of the astigmatic axis of the TORIC-Intraocular lens by detecting the astigmatic axis mark based on the retro-illumination image. 
 
     
     
       4. The Ophthalmic apparatus according to  claim 3 , wherein the computing unit is further adapted to obtain an axial misalignment amount that is a misalignment amount between the direction of the corneal astigmatic axis and the direction of the astigmatic axis of the TORIC-Intraocular lens. 
     
     
       5. The Ophthalmic apparatus according to  claim 1 , wherein the computing unit is further adapted to obtain an optical center position of the TORIC-Intraocular lens by processing the retro-illumination image, to obtain a corneal center position of the examinee's eye based on the cornea reflection image, and to detect a misalignment amount between the corneal center position and the optical center position. 
     
     
       6. The Ophthalmic apparatus according to  claim 1 , further comprising:
 an ocular axial length measuring optical system for projecting measurement light on the examinee's eye and detecting interference light formed from reflection light from the examinee's eye, wherein 
 the illuminating optical system is adapted to project the measurement light of the ocular axial length measuring optical system. 
 
     
     
       7. The Ophthalmic apparatus according to  claim 1 , wherein the light projecting optical system and the first imaging optical system constitute a keratometer optical system or an anterior segment cross-sectional image imaging optical system. 
     
     
       8. A method of obtaining a retro-illumination image of an examinee's eye by use of the ophthalmic apparatus according to  claim 1 , the method comprising:
 obtaining the direction of the corneal astigmatic axis of the examinee's eye before an operation using an intraocular lens and the retro-illumination image; 
 superimposing the first target on the retro-illumination image; and 
 obtaining the retro-illumination image on which the first target is superimposed. 
 
     
     
       9. A method of obtaining a retro-illumination image of a examinee's eye by use of the ophthalmic apparatus according to  claim 1 , the method comprising:
 obtaining the direction of the corneal astigmatic axis of the examinee's eye after an operation using an intraocular lens and the retro-illumination image; 
 superimposing the first target on the retro-illumination image; and 
 obtaining the retro-illumination image on which the first target is superimposed. 
 
     
     
       10. The ophthalmic apparatus according to  claim 1 , further comprising an output unit for outputting the retro-illumination image on which the first target is superimposed. 
     
     
       11. The ophthalmic apparatus according to  claim 4 , further comprising an output unit for outputting the axial misalignment amount together with the retro-illumination image. 
     
     
       12. The ophthalmic apparatus according to  claim 5 , further comprising an output unit for outputting the misalignment amount together with the retro-illumination image.